OBJECTIVE The aim of the study was to investigate surgical indication and long-term outcome of carotid endarterectomy (CE) in young adults. METHODS Between 1973 and 1990, 1693 patients underwent CE. Forty-nine patients (group T) 35 to 45 years of age who had carotid artery stenosis greater than 70%, formed the basis for the analysis. They were compared with two additional groups of patients older than 45 years of age selected from the entire series. Group 2 was randomly chosen to determine differences in risk factors, associated diseases, operative indications, preoperative findings, and outcome. Group 3 was matched with patients in group 1 for sex, risk factors, associated diseases, preoperative findings, and operative indications to assess the importance of age in determining the short- and long-term outcome of CE. RESULTS Postoperative mortality, cerebrovascular accidents, and cardiac complications in patients of group 1 (2%, 2%, and 2%, respectively) were similar to those of the other groups (p = NS). During the follow-up (76.7 +/- 3.6 months; range, 1 to 120 months) the incidence of strokes and transient ischemic attacks in group 1 was lower than in group 2 (p < 0.05) but similar to group 3 (p = NS). Ten-year disease-free intervals were 75.7%, 58.7%, and 77.6%, respectively, for groups 1, 2, and 3. Mortality rate unrelated to cerebrovascular disease was similar between group 1 and group 3 (p = NS) but was higher in group 1 than in group 2 (p < 0.02). Ten-year survival rates were 46.1%, 71.7%, and 55.5%, respectively, for groups 1, 2, and 3. CONCLUSIONS CE in patients younger than 45 years of age is a safe procedure with low operative risks and good disease-free intervals. However, life expectancy is poor because of the high incidence of deaths resulting from complications of atherosclerosis.